The objective of the Phase I effort of this project is the evaluation of an advanced digital electronic camera for mammographic screening. The camera consists of a cooled, slow-scan CCD based electronic still camera capable of extremely low readout noise, and high contrast and spatial resolution. The CCD will be coupled to an x-ray scintillator with a demagnifying collimated fiber optic. Preliminary investigations of a system similar to the one to be used in this study indicate that the approach should give results that are x-ray photon shot noise limited. The Phase I effort will by limited to physical experiments to determine signal-to-noise ratio and contrast ratio capabilities in comparison with the film/screen combinations currently in use. Clinical trials will be arranged at the University of Arizona to evaluate the effectiveness of digital breast needle localization.